Forum Discussion
Ignored constraints on non linear problem
Hello all, I'm working on a final studies project and i'm facing some issue on the Xpress Solver. The versions i'm using are Xpress-IVE Version 1.24.00 64bit, Xpress Mosel Version 3.4.2 and Xpress ...
The nonlinear solvers in Xpress are local solvers. This means that while the solvers are written for scalability, there is no gaurante that they will find a global optimum, or always find a feasible solution, unless your problem is convex.
What happens when you fix a variable, is that you are changing both the problem statement, and the initial point that Xpress will use, making the problem easier for Xpess in this case.